[Android]_ch8.2_SQLite資料庫查詢

[Android]_ch8.2_SQLite資料庫查詢



public ArrayList<String> queryDB(){

SQLiteDatabase db=getWritableDatabase();

Cursor cursor=db.rawQuery("SELECT * FROM teacher;", null);

ArrayList<String> list=new ArrayList<String>();

while(cursor.moveToNext()){

String msg="";

for (int i = 0; i < cursor.getColumnCount(); i++) {

msg=msg+cursor.getString(i)+"\t";

}

list.add(msg);

}

return list;

}



btn2.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

ArrayList<String> list=dbhp.queryDB();

StringBuilder sb=new StringBuilder("查詢結果"+list.size()+"筆如下:\n");

if(list.size()>0){

for(int i=0;i<list.size();i++){

sb.append(list.get(i)+"\n");

}

}else{

sb.append("查詢不到資料...");

}

tv1.setText(sb);

}

});